In a normal situation when a plug-in hybrid vehicle should be charged, the driver parks the hybrid vehicle at a charging station, turns off the engine and connects the charging cable to the hybrid vehicle by inserting the plug of the charging cable into the charging socket of the hybrid vehicle. The hybrid system and the charging station starts to communicate and the hybrid system requests charging whereby the charging station starts to deliver electrical energy to the drive assembly battery of the hybrid vehicle.
It is important that the vehicle remains stationary and does not roll or drive away. This is especially important when a charging cable is connected to the vehicle. The driver would normally apply the parking brake when parking the hybrid vehicle.
US 2010/0320018 describes a method for preventing drive away or roll away of a plug-in hybrid vehicle during charging. Driveway and roll away is prevented by disabling the hybrid vehicle by means of a mechanical restraint that locks the parking brake, or locks the gear in a park position. The mechanical restraint is applied by the vehicle when a charging process is detected. The driver is informed audibly or visibly by the disabled hybrid vehicle why the vehicle cannot be driven, see FIGS. 6 and § 0007-§ 0010 in US 2010/0320018. FIG. 7 of US 2010/0320018 shows an embodiment wherein charging is only allowed when the vehicle has been parked.
US 2011/0178663 describes a method for preventing drive away of a hybrid vehicle during charging. The vehicle is disabled when a charging cable is attached to the vehicle. If the driver makes a starting attempt, a message is shown. The vehicle is enabled when the charging cable is removed, see FIGS. 2 and § 0023-§ 0025 in US 2011/0178663.
In addition to the drive assembly battery storage of the hybrid system, such as a high voltage storage, the hybrid vehicle would normally be provided with an accessory battery, such as a low voltage battery storage, for powering accessories, such as lights, heat, air-conditioning and user interface. The accessory battery can be charged by an external charger or by means of a generator driven by the internal combustion engine.
In addition to charging the drive assembly battery storage, the driver may need additional energy when charging the drive assembly battery storage, for example for using the accessories of the hybrid vehicle, or charging the accessory battery.
A problem is that the charging station may have a limited number of charging cables, and may be able to provide only a limited amount of electrical power for charging purposes. Thus, the driver would want to use all available power for the time-consuming charging of the drive assembly battery storage, but would also like to be able to use accessories without risking running out of power in the accessory battery. Thus, there is a need for a hybrid vehicle that may be charged with electrical power and at the same time have power to accessories of the vehicle.